1. Field of the Invention
The invention is directed to a lying surface for a bed, in particular a healthcare and/or hospital bed.
It is generally known to provide a decubitus prophylaxis in particular to long-term hospital or healthcare patients. Here, a stimulation and a partial pressure relief of the body to be treated is obtained by local minimal movements of the lying surface. Clinical studies have proven the medicinal efficiency of such systems.
2. Description of Related Art
For decubitus prophylaxis and for pain therapy, prior art knows special pneumatic mattresses. Further, for example from WO-A-03/028511, an underspringing for mattresses is known, i.e. a mattress support surface with mattress supporting bars extending transverse to the length of the bed, at least several of which are adapted to be purposefully moved up and down pneumatically. Similar systems with fluid-controlled actuators (i.e. pneumatically or hydraulically operated actuators) are known from EP-A-0 934 740 and EP-A-0 734 742, U.S. Pat. No. 5,109,558, U.S. Pat. No. 5,060,326, and WO-A-03/045300. Besides fluid-operated actuators, these further documents mentioned also describe electromotive actuators. Further systems of the above type are described in EP-A-0 788 786 and U.S. Pat. No. 5,626,555.
The basic problem of the use of actuators to generate local lifting movements within a lying surface of a bed is the rather substantial noise produced by such systems. Both pneumatic and electromotive actuators generate noise when in operation, which may be perceived by the patients or the persons to be cared for as irritating and disturbing.